Modifications to support ImsResolver and adds Tests

1) Adds unit tests for ImsService and related classes.
2) Modifies the ImsPhoneCallTracker to support the new ImsResolver.
3) Modifies the ImsServiceController to relay ImsService status callbacks.

Test: Unit Tests added
Merged-In: Ibcb001ce13e0bcc21f02deede64f7ee8f1549e59
Change-Id: Ibcb001ce13e0bcc21f02deede64f7ee8f1549e59